Evolving the Global Climate Observing System to Today's Needs

Since 1992, the Global Climate Observing System (GCOS) has been operating to ensure that information needed to address climate-related questions are obtained and made available to all potential users. Now, this is more important than ever and GCOS is adapting in order to fulfil the growing demand for robust climate observations.

The GCOS Upper Air Network (GUAN), established in 1998, which monitors the upper atmosphere has proven to be of significant benefit in maintaining a “baseline” global network of upper-air observations. However, as stated in the new GCOS Implementation Plan, there is a need to review the benefits and requirements of the GUAN to ensure that it is relevant and cost effective for the future and can deliver a baseline network within a system of tiered networks – reference, baseline and comprehensive. To undergo this review, a task-team of experts will meet in Lindenberg, Germany, home of the GCOS Reference Upper Air Network (GRUAN) lead-centre, in December.

In recent years, the need to adapt to, and eventually mitigate, climate change has become a driver for systematically coordinating climate observations. Now, more accurate information on fluxes across the traditional domains – atmosphere, ocean and land – is required in order to improve our understanding of the major climatic cycles (carbon, water and energy). The GCOS Surface Reference Network’s (GSRN) vision is a monitoring system that provides highly accurate and meteorologically traceable observations with well characterized uncertainties and long term stability. It will measure traditional parameters like precipitation and temperature as well as parameters like soil moisture and leaf area. A task team of ten leading experts will meet in November in Maynooth, Ireland, to prepare a roadmap for the establishment of the network.

Another driving force for improving climate observations is our still limited understanding of recent changes in the dynamics of climate-induced extreme events. The problem becomes clear when looking at precipitation observations. A well-established and mature observation system is in place for precipitation. For climate purposes, data is still rarely observed and stored for climate applications on a time scale shorter than one day. Heavy precipitation events, however, requires higher resolution to capture their dynamic. Our understanding of these extreme events is still limited. On the other side, weather radar stations exist in many countries of the world for fore- and nowcasting, but their data is rarely saved for climate applications and their data management is not coordinated. In order to close the gap, GCOS established an international task team on the use of weather radar for climate studies. This task team of radar experts met for the first time in August in Helsinki, Finland, and developed a plan on how to make use of radar observations for climate applications.

Related to heavy precipitation are storm events, which amongst the most frequent extremes and related to disasters such as floods. Still, there is a demand for more accurate data to understand global changes in storminess. One potential indicator that can be used as a proxy for monitoring severe convection and hence precipitation is lightning. In recent years, measurements of lightning have become more extensive and new satellite instruments have further enhanced measurement coverage. This helps to improve estimates of severe storm intensity and supports early warnings for severe weather. In regard of climate monitoring, lightning is a valuable indicator to track and understand trends in convective events. Therefore GCOS added lightning to the list of Essential Climate Variables (ECV) in the 2016 plan and is currently establishing a task team that will define requirements and standards for climate monitoring of lightning.

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